Irrigation was a technique for distributing water.
While on Amerind, James T. Kirk proposed a system to irrigate the local fields and double the food supply. It would depend on a canal bringing water from a lake to the lodge. (TOS: "The Paradise Syndrome")
In 2370, Kira Nerys discussed irrigating the Trilar Peninsula with Minister Rozahn for an entire day. She was surprised that Benjamin Sisko knew, but he explained that he'd overheard her shouting at a monitor for the last two days. (DS9: "Sanctuary")
Shortly before the colony was attacked by the Jem'Hadar, New Bajor had established an irrigation system that was said to be a sight to see. (DS9: "The Jem'Hadar")
Dinaal contained an irrigation facility that provided water to half a subcontinent. A chief engineer from the facility was being treated on Hospital Ship 4-2 in 2377. (VOY: "Critical Care")
While acting as a priest in the Fair Haven holoprogram, The Doctor told a story about two feuding farmers, one of which at one point clogged an irrigation ditch belonging to the other. (VOY: "Spirit Folk")